Beer attenuates too much too fast

Question

Beer attenuates too much too fast

Gustavo Arias Méndez

2018年9月24日 15:39

I am brewing with fermentis S-04 and from experience (three years ago) I know that this yeast is slow.

This weekend I brewed a small batch and today the attenuation is 83% (according to the yeast's specification it should be 75% at most) only 4 days have passed.

I suspect it's contamination, could it be something else?

Edit: Its a 18 liter (4.7 gal) batch and the recipe is 5Kg (11 pounds) of 6-rows base malt and 1 Kg (2.2 pounds) of cane sugar

Note: I brew in México's Michoacan state, my temp ranges from 15 to 26

Topic primary-fermentation attenuation contamination homebrew

Category Mac

Philippe · Accepted Answer · 2018年9月24日 15:39

The mash temperature can also have an effect on attenuation (fermentability).

I will quote Denny Conn, from this post: Yeast attenuation and fermentable sugars

Yeast attenuation is determined by the yeast lab under laboratory conditions, and it is only a way of comparing one yeast relative to another using the same wort. You may or may not achieve the attenuation that is listed for the yeast. It may be less, it may be greater than listed. That depends on the fermentability of your wort.

Also, the fermentation temperature can affect the speed of fermentation, the colder the slower. Many variables that can explain your concerns, so contamination is possible, but not necessarily it.

Frazbro · Accepted Answer · 2018年9月21日 06:23

I have never found S-04 to be slow. Even on 500L batches, I've had beers with S-04 ferment dry in under 5 days. It also flocs out like a ton of bricks. Are you confident you don't have a contamination with another, more attenuative yeast? Are you also confident you got your OG and FG readings right, and calculated the AA right? As jsolarski says, without a recipe and more details, it's hard to say what's going wrong for you.

jsolarski · Accepted Answer · 2018年9月20日 19:18

smaller the batch, usually the faster the fermentation will happen. my 1.5 gal batches took less then 5 days to reach F.G.

also with out a recipe posted, a more ferment-able wort will attenuate more. the given attenuation on yeast are for lab conditions.

if it continues then yes, it could be contaminated, but if it stops, then its just the yeast doing its thing.

Beer attenuates too much too fast

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